Multi-component knee implant assembly with combined articulating and belt support and traveling surfaces

ABSTRACT

A joint assembly incorporated into reconditioned end surfaces established between an upper bone and an opposing lower bone. The assembly includes a pair of first components anchored into reconditioned bone end surfaces of a first joint defining bone and exhibiting a flexible and band-shaped loop displace-ably supported along exposed undersides established between outer portions which are assembled around the bands. A second component anchored into a second reconditioned end surface of a second joint defining bone exhibits a planar support surface upon which said bands are in contact with and displace during articulating motion of the bones. Entrapment pockets are formed within the first components for collecting wear particles and debris resulting from displacement of the belt.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Division of application Ser. No. 13/597,417 filedon Aug. 29, 2012. Application Ser. No. 13/597,417 claims the benefit ofU.S. Provisional Application 61/528,904 filed on Aug. 30, 2011, thecontents of which are incorporated herein in their entirety.

FIELD OF THE INVENTION

The present invention discloses an artificial joint assembly, such as isparticularly configured for employing as a retrofit knee joint, andwhich combines pairs of end anchored artificial components incorporatedinto each of first and second reconditioned joint defining surfaces forproviding increased wear life in tandem with evenly distributed wearpattern/profile as well as enhanced flexibility and mobility.

BACKGROUND OF THE INVENTION

The prior art is well documented with examples of artificial kneeimplant assemblies. These include such as the spherical knee jointprosthesis of Bosredon, U.S. Pat. No. 6,117,175, the total knee implantof Byrd et al., US 2010/0191342 and the artificial implant component andmethod for securing disclosed in Elias, U.S. Pat. No. 5,480,443.

SUMMARY OF THE INVENTION

The present invention discloses a joint assembly incorporated intoreconditioned end surfaces established between an upper bone and anopposing lower bone. The assembly includes a first component anchoredinto a first of the reconditioned bone end surfaces and exhibiting afirst exposed support surface and a second component anchored into asecond of the reconditioned bone end surfaces and exhibiting a secondexposed support surface further including a flexible and conveyableclosed loop belt relatively displaceable upon contact with the firstsupport surface.

At least one of the components may further exhibit an arcuate shapedsupport surface and can be constructed of at least one of a metal,plastic, polymer or composite material. In one desired arrangement, afirst pair of components are arranged at a first side of said assemblyaffixed to reconditioned opposing surfaces associated with first andsecond knee joint defining bones, with a second identical pair arrangedat an opposite second side. This can further include a ½ implantassembly associated with a selected side of the joint defining bones,and such as in combination with a natural remaining portion of thejoint.

The second component may further incorporate a subassembly including apair of side assembleable outer portions capturing the belt therebetweensuch that an upper portion of said belt is exposed for contacting saidfirst component. Each of the side assembleable outer portions furtherincludes opposing and mating receiving channels for supported the beltin conveyable fashion therebetween. The side assembleable outer portionseach may also include aligning tab and slot portions forinter-assembling about the belt.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the attached drawings, when read incombination with the following detailed description, wherein likereference numerals refer to like parts throughout the several views, andin which:

FIG. 1 is a perspective view of a knee implant assembly according to afirst embodiment of the invention;

FIG. 2 is an exploded view of the multi-component assembly of FIG. 1 andbetter illustrating the reconditioned end-configurations establishedbetween the upper femur and lower tibia leg bones combined with thepairs of upper bone secured arcuate portions and lower bone securedconveyor belt and supporting portions, a selected one of which isfurther depicted in subassembly exploded fashion to better illustratethe configuration of the inner conveying belt and outer sideassembleable body portions;

FIG. 3 is an illustration of a knee implant assembly according to afurther preferred variant;

FIG. 4 is an exploded view of the assembly of FIG. 3 and betterillustrating the further reconditioned end-configurations establishedbetween the upper femur and lower tibia leg bones combined with thepairs of upper bone secured conveyor belt and supporting portionscombined with the lower bone secured platform support for receiving theexposed conveyor belt portions; and

FIG. 5 is a plan cutaway of such as the upper bone in FIG. 3 and betterillustrating the three piece construction of the side by side arrangedpair of conveyor belt and support portions and including debrisentrapment pockets defined in surface locations of the mating supportportions arranged on an underside of the intermediate supported conveyorbelt.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As will be disclosed with succeeding reference to the several depictedembodiments, the present invention discloses an artificial jointassembly, such as is particularly configured for employing as a retrofitknee joint, and which combines respective upper and lower pairs ofartificial components incorporated into first and second reconditionedjoint defining surfaces, such as for providing increased wear life alongwith both enhanced flexibility and mobility.

The joint assemblies described herein are particularly configured forsuch as in situ reconditioned installation within a patient's kneeassembly (between the lower end of the upper femur bone andcorresponding upper end of the lower tibia bone), however it is furtherunderstood that certain applications could in theory include other jointapplications, either human or other mammalian. For purposes of ease andclarify of illustration, the various embodiments depicted further do notinclude reference to additional necessary components of the knee joints,such as including the patella (knee cap) and associated muscles, tendonsand ligaments, the inclusion of which are assumed and which collectivelydefine a functioning knee joint.

Referring now to FIG. 1, a perspective view is generally shown at 10 ofa knee implant assembly according to a first embodiment of the inventionand which is incorporated between an upper leg (femur) bone 2 and alower leg (tibia) bone 4 (and with which an associated fibula bone isalso not depicted). The present invention contemplates such as in situreconditioning of the bone ends, illustrated by conditioned end profiles6 configured into the bottom most end surface of the femur 2, as well asopposing upper end facing and recessed profiles 8 defined in the uppermost end of tibia 4 with additional bridging location 9 defined betweenthe substantially hemispherical shaped recessed profiles 8.

As best shown in FIG. 2, the recesses 8 are depicted by a spaced apartpair of generally three dimensional semi-circular profiles eachincluding an arcuate recessed profile bounded along opposites sides byplanar parallel spaced end walls as shown and which are established atright and left sides of the joint zone. The recessed profiles 8 aredefined in reconditioned flat surfaces 11 which are separated by theintermediate bridging location 9.

Such reconditioning occurs following incision or removal of anyremaining damaged bone and/or cartilage associated with the damagedjoint and during an appropriate surgical procedure utilizing medicaldrilling, boring and shaping instruments in order to recondition thejoint defining bone ends and to create the desired shaping and profileof the joint. As previously indicated, it is advantageous to refashionthe joint end profiles in situ during an appropriate surgical procedure,a further objective being to retain or repair, where possible, naturalligament, cartilage and muscle associated with a normal functioningjoint.

Although not shown, such reconditioning can be employed with minimalinterference to such necessary additional elements of the jointincluding each of the patella or knee cap, ligaments, muscles andtendons. Without limitation, it is further understood that the jointassemblies described in each of the illustrated variants can beintegrated into either of human or synthetic bones (such as which canalso contemplate both human and synthetic bones in a single jointapplication), with such joint assemblies also capable of surgicallyimplanted in either total (or paired) or partial (one side or one halfof the joint) manner concurrent with any necessary degree ofrefashioning or removal of damaged bone or joint.

Referring to FIG. 1 again in collaboration with exploded view of FIG. 2,the multi-component assembly 10 better illustrates the reconditionedend-configurations 6 and 8 established between the upper femur 2 andlower tibia 4 leg bones, combined with each of a pair of upper bonesecured arcuate (or track) portions 12 and 14 and lower bone secured andconveyor belt integrated subassemblies 16 and 18. A selected subassembly16 is further depicted in subassembly exploded fashion to betterillustrate the configuration of an inner conveying belt 20 and outerside assembleable body portions 22 and 24, with correspondingsubassembly 18 depicted in assembled fashion but being identical inconstruction.

Each of the components 12-18 are constructed of any arrangement ofmetal, polymer, plastic, composite or other suitable material, with itfurther being understood that the individual pairs of components can bearrayed with any pattern of alternating materials. In this fashion, thedesired wear properties and profiles are adjusted in part based upon thematerial selection of the individual components with concurrentobjectives being both equalization of overall wear patterns establishedbetween the respective pairs of components and determining thosesituations in which metal on metal or plastic on plastic contact betweenthe components is either desired or, more often, not.

Both the upper bone secured arcuate (or track) portions 12 and 14 andlower bone belt supporting subassemblies 16 and 18 are anchored inseating fashion within the inner recessed profiles 6 and 8 of the femur2 and tibia 4 bones, respectively, by use of a suitable medical cement(it further being understood that suitable bone adhesion can also beassisted or promoted by inner marrow in given circumstances). The uppertrack portions 12 and 14 each exhibit and arcuate exposed surface (seeat 26 and 28 in FIG. 2), with inner (reverse side) extending stems 30and 32 being recess mounting within the mating recess configurations 6defined in the joint end defining face of the upper femur bone 2.

Width extending apertures 34 and 36 are further defined in the stems 30and 32 and can also receive like widthwise inserting pins 35, uponinstallation of the track portions as depicted by arrows 37. The pins 35extend through mating and aligning apertures formed widthwise throughthe femur bone 2 (see further at 38) to further affix the track portions12 and 14 within the joint end defined surface in the femur bone 2.

The lower bone secured belt conveyor and support subassemblies 16 and 18each further exhibit an inner flexible and closed looped band (see againselected band shaped belt 20 depicted in exploded fashion with respectto exploded subassembly 16 with an identical such band 16′ depicted forcorresponding assembled subassembly 18. The outer assembleable portions22 and 24 (typically a harder plastic as opposed to the inter-disposedflexible band 20) each exhibit opposing receiving channels (see as shownat 40 for selected assembleable side portion 24 with opposing and matingreceiving cannel for portion 22 being hidden from view) and areinter-assembled with the band 20 supported therebetween in conveyablefashion therebetween.

Opposing pairs of tab and slot or other suitable fasteners are providedon inside faces of the outer support portions 22 and 24 (see as furtherdepicted at 42 disposed upon inside facing surface of side portion 24,with mating receiving locations in opposing support portion 22 againhidden from view). Additional projecting edge locations 44 and 46 aredefined on opposing inner surfaces of the support subassemblies and abutagainst configured sides 47 and 49 (again FIG. 2) of the bridginglocation 9 of the refashioned end surface of the lower tibia 4 combinedwith additional bottom convex surfaces 48 and 50 seating within theafore-described mating recessed profiles 8 associated with therefashioned tibia end face.

In this fashion, the path of travel of the upper portion arcuate exposedsurfaces 26 and 28 causes the belts 20 to be fairly easily displacedalong the tracks defined between the side assembleable supports 22 and24 and in such a fashion that ease of bending motion is achieved for thejoint assembly. As again previously indicated, additional configurationsof muscles, ligaments, tendons and patella (knee cap) are provided andcan include both natural and/or synthetic materials which can beimplanted or reconstructed in order to provide a dynamic and long-termimplantable assembly.

Proceeding to FIGS. 3-5 in succession, respective perspective, explodedand plan cutaway views are provided of knee implant assembly accordingto a further preferred variant and as generally depicted at 52. As bestshown in FIG. 4, a different set of reconditioned and recess configuredprofiles are fashioned within the joint end faces of the femur 2 andtibia 4, and are defined respectively at 54 and 56, respectively and incomparison to the configuration of the corresponding profiles 6 and 8 inFIG. 2.

The upper recess profiles 54 each exhibit a substantially threedimensional shaped cavity for receiving a pair of individual shapedbodies including upper conveyor and lateral assembleable supportingportions (see as defined by individual exploded subassembly 58 andfurther assembled subassembly 60). The lower recess profiles 56 eachdefine a pair of inwardly recessed holes exhibited on sides of agenerally planar shaped refashioned end face of the lower tibia bone,with the refashioned projecting bridging portion establishedtherebetween at 62.

A one piece support platform 64 exhibits a modified U shape with anarrow intermediate bridging location and widened side ear or lobesurfaces 66 and 68. Additional pairs of extending posts 70 and 72 areintegrally disposed with integrally defined and underside projectinglocations of the platform 64 and such that the posts are anchored(cemented) into the bone end surface refashioned recesses 56 in a mannerwhich permits the platform 64 to be secured thereupon, such as furtherdepicted in FIG. 3.

The construction of the belt conveyor and side assembled supportsubassemblies 58 and 60 is largely the same as previously referenced asto corresponding subassemblies 16 and 18 in FIG. 2, with the exceptionthat the belt and support assemblies are anchored within an underside ofthe upper femur bone 2 as opposed to the upper joint defining face ofthe lower tibia bone 4 as in FIGS. 1 and 2. Similar to the firstpreferred embodiment, and referring to selected exploded subassembly 58in FIG. 4, a flexible and band shaped loop or belt 74 is configured formounting within opposed assembling inner facing surfaces of outerassembleable supports 76 and 78, each of which again further defininginner receiving channels or guides (see at 80 for selected side support78).

Additional tab and slot assembly locations, see as depicted by tabs 82defined in exposed and selected side support 78 (with again mating slotsassociated with opposing face of support 76 hidden from view butdepicted in reference to cutaway FIG. 5), and which facilitateinter-assembly of the side supports 76 and 78 in order to establish thethree dimensional assembly further depicted by selected subassembly 60.To facilitate mounting, apertures 84 and 86 defined in widthwiseextending fashion through the assembled subassemblies 58 and 50 align,upon installation of the subassemblies into the recessed endconfigurations 54 of the femur 2, with a further widthwise extendingaperture 88, such as again for receiving a pin or the like (such asagain depicted at 35) for further assisting in anchoring thedisplaceable belt supporting subassemblies 58 and 60 into position.

Referring finally to FIG. 5, a plan cutaway is shown of such as theupper femur bone 2 in FIG. 3 and better illustrating the three piececonstruction of the side by side arranged pair of conveyor belt andsupport portion subassemblies 58 and 60. The inter-engaging nature ofthe subassembly component halves, such as at 76 and 78, is betterdepicted in FIG. 5 and which illustrates receiving slots (see at 90)associated with selected side assembleable portion 76 (the inner facingside of which is hidden in FIG. 4) for receiving a selected and aligningtab 82.

Of particular note in FIG. 5, each of the subassemblies 58 and 60include circumferential disposed pairs of debris entrapment pocketswhich are defined along inside surface locations of the sideassembleable and mating support portions and such that the entrapmentchambers or pockets are arranged along undersides of the intermediatesupported and displaceable conveyor belts/bands. These are particularlyshown at 92 and 94 arranged along inner sides of the flexible band 74associated with belt conveyor subassembly 58 and further at 96 and 98arranged along corresponding inner sides of the flexible band associatedwith the other belt conveyor subassembly 60.

Each of the entrapment pockets or chambers further include narrowedcommunicating locations 100, 102, 104 and 106 in relation to associatedentrapment chambers 92, 94, 96 and 98 in contact with the innerdisplacing surfaces of the flexible bands (e.g. again as shown byexample at 74) and which lead to an enlarged collecting reservoir forsecurely holding micron sized debris resulting from progress wearprofiles along the joint assembly, and in particular wearing away of thetranslating belts over time. In this fashion, long term functionality isachievable for the joint assembly and without permitting theaccumulating debris to otherwise compromise the functionality of thejoint.

As previously explained, additional variants of the joint assembliescontemplate a first side or half being reconditioned in the mannerdepicted herein, with a further side or unreconstructed half retainingits original joint defining structure and which, to the extent possible,is unaffected by the reconditioning performed to the implanted half ofthe joint assembly.

Having described my invention, other and additional preferredembodiments will become apparent to those skilled in the art to which itpertains, and without deviating from the scope of the appended claims.

We claim:
 1. A joint assembly incorporated into reconditioned endsurfaces established between an upper bone and an opposing lower bone,said assembly comprising: a pair of first component subassembliesadapted to being anchored to reconditioned end surfaces of a first jointdefining bone, each of said first component subassemblies having aflexible and band-shaped loop displace-ably supported between a pair ofouter assemble-able portions, such that exposed locations of said bandsextend along open undersides established between said assemble-ableouter portions; and a second component anchored into a secondreconditioned end surface of a second joint defining bone, said secondcomponent exhibiting a planar support surface upon which said bands arein contact with and displace during articulating motion of said jointdefining bones.
 2. The joint assembly as described in claim 1, each ofsaid pair of first components further exhibiting an arcuate shapedsupport surface.
 3. The joint assembly as described in claim 1, each ofsaid first and second components further being constructed of at leastone of a metal, plastic, polymer or composite material.
 4. The jointassembly as described in claim 1, each of said pair of first componentsfurther comprising any of anterior or posterior, distal and proximate ormedial and lateral components associated with a selected side of saidjoint defining bones.
 5. The joint assembly as described in claim 1,each of said outer assemble-able portions further comprising opposingand mating receiving channels for supported said belt in displaceablefashion therebetween.
 6. The joint assembly as described in claim 5,said outer assemble-able portions each further comprising aligning taband slot portions for inter-assembling about said belt.
 7. The jointassembly as described in claim 6, further comprising circumferentialextending debris entrapment pockets along inside surface locations ofsaid outer assemble-able portions and in communication with translatingsurfaces of said belts.
 8. The joint assembly as described in claim 7,further comprising inner surfaces of each of said belts having narrowedlocations communicating said belts with said entrapment pockets forcollecting and holding debris resulting from progressive wearing of saidbelts.
 9. The joint assembly as described in claim 1, said secondcomponent further comprising a generally “U” shape with undersideprojecting posts adapted to mount within aligning apertures defined insaid second reconditioned bone end surface.
 10. A process for in-situreconditioning of opposing ends of femur and tibia joint defining bonesand for installing into the reconditioned ends an artificial jointassembly, comprising the steps of: incising a patient location to accessdamaged opposing ends of the joint defining bones; removing damaged ordetached portions of bone and cartilage; refashioning each of the jointdefining bone ends including forming at least one three dimensionalrecessed profile in each bone end; installing a pair of first componentsubassemblies into a pair of refashioned profiles defined in the firstof the reconditioned bone ends, such that anchoring portions of each ofthe first component subassemblies seats within the three dimensionalrecessed profile, the first component subassemblies each exhibiting aflexible and band-shaped loop displace-ably supported along exposedundersides established between outer portions which are assembled aroundsaid bands; and installing a second component into the other of thereconditioned bone ends such that an anchoring portion of the secondcomponent seats within the three dimensional recessed profile, thesecond component exhibiting a planar support surface upon which saidbands are in contact with and displace during articulating motion ofsaid joint defining bones.
 11. The process as described in claim 10,said step of refashioning a first of said joint defining bone endsfurther comprising the step of forming a semicircular base surfacebounded along opposite sides by a pair of planar and spaced apart endwalls.
 12. The process as described in claim 11, said step of installinga pair of first component subassemblies further comprising inserting apair of pins in opposing and widthwise extending directions throughapertures extending inwardly from opposite sides of the first jointdefining bone and in communication with said three dimensional recessedprofiles, said pins seating within aligning apertures defined in outerselected assembleable portions of each of said pair of first componentsubassemblies.
 13. The process as described in claim 10, said step ofrefashioning a second of said joint defining bone ends furthercomprising fashioning a continuous planar surface along each of firstand second sides of the bone and which is interconnected at a forwardend, a refashioned bridging portion extending at a generally centrallocation of the second bone end and around which is supported the secondcomponent.
 14. The process as described in claim 13, said step ofrefashioning further comprising forming apertures in the planarreconditioned surfaces of the second bone end, these receiving undersideextending mounting posts associated with said second component.
 15. Ajoint assembly incorporated into reconditioned end surfaces establishedbetween an upper bone and an opposing lower bone, said assemblycomprising: at least one first component subassembly adapted to beinganchored to a reconditioned end surface of a first joint defining bone,said first component subassembly having a flexible and band-shaped loopdisplace-ably supported between a pair of outer assemble-able portions,such that exposed locations of said band extends along open undersidesestablished between said assemble-able outer portions, each of saidouter assemble-able portions further having opposing and matingreceiving channels for supported said belt in displaceable fashiontherebetween; and a second component anchored into a secondreconditioned end surface of a second joint defining bone, said secondcomponent exhibiting a planar support surface upon which said band is incontact with and displace during articulating motion of said jointdefining bones.
 16. The joint assembly as described in claim 15, saidouter assemble-able portions each further comprising aligning tab andslot portions for inter-assembling about said belt.
 17. The jointassembly as described in claim 16, further comprising circumferentialextending debris entrapment pockets along inside surface locations ofsaid outer assemble-able portions and in communication with translatingsurfaces of said belts.
 18. The joint assembly as described in claim 17,further comprising inner surfaces of each of said belts having narrowedlocations communicating said belts with said entrapment pockets forcollecting and holding debris resulting from progressive wearing of saidbelts.
 19. The joint assembly as described in claim 15, said secondcomponent further comprising a generally “U” shape with undersideprojecting posts adapted to mount within aligning apertures defined insaid second reconditioned bone end surface.